It is possible to change the expression evaluator in two ways :
- One may change the way unrecognized commands are treated. The default way is to send them to the expression evaluator using the function Evaluate.
- Another way is to send instructions in sequences between [ and ] instructions (cf. 4.3.4) to something else than the expression evaluator. The default behaviour or the interpreter is to send these instructions to the function convert_float.
This can be done independently in each thread. This is explained with more details in 10.4.